By using data from ESA’s Gaia spacecraft, astronomers have discovered a new Milky Way satellite in the constellation Antlia. The newly found dwarf galaxy, named Antlia 2, is several times larger when compared to other systems of similar luminosity and 424,000 light-years away from Earth.
Scientists estimate that dozens of smaller galaxies orbit the Milky Way, pulled in by our galaxy’s intense gravitational forces. Now, a team of researchers using data from the European Space Agency’s (ESA) Gaia spacecraft, has discovered a new satellite galaxy named Antlia 2 (Ant 2) with a host of strange features.
To make this discovery, a research team, led by Gabriel Torrealba of Academia Sinica in Taiwan, used data from the Gaia spacecraft’s second data release. They used the data to search for Milky Way satellites, or objects orbiting the Milky Way. They looked at the motion and magnitude of stars and the brightness and variability of objects near the Milky Way to find a group that was moving together in a way that indicated they were all part of a single dwarf galaxy.
Ant 2, which researchers estimate to be about 11.2 billion years old, is enormous, about one-third the size of the Milky Way. It’s about the same size as the Large Magellanic Cloud (LMC), another nearby dwarf galaxy, but is much more lightweight. The new dwarf galaxy is extremely diffuse, meaning its component stars, gas and dust are spread out over a very large area. In fact, Ant 2 is the most diffuse object ever detected, according to a statement.
This means that the galaxy doesn’t give out much light. So, while Ant 2 might be the same size as the LMC, it’s actually 4,000 times fainter.